Detection of Mycobacterium tuberculosis bacilli in bio-aerosols from untreated TB patients

Abstract

Tuberculosis (TB) is predominantly an airborne disease. Background However, quantitative and qualitative analysis of bio-aerosols containing the aetiological agent, , has proven very Mycobacterium tuberculosis (Mtb) challenging. Our objective is to sample bio-aerosols from newly diagnosed TB patients for detection and enumeration of bacilli. Mtb : We monitored each of 35 newly diagnosed, GeneXpert Methods sputum-positive, TB patients during 1 hour confinement in a custom-built Respiratory Aerosol Sampling Chamber (RASC). The RASC (a small clean-room of 1.4m ) incorporates aerodynamic particle size detection, viable and non-viable sampling devices, real-time CO monitoring, and cough sound-recording. Microbiological culture and droplet digital polymerase chain reaction (ddPCR) were used to detect in each of the bio-aerosol collection Mtb devices.: was detected in 27/35 (77.1%) of aerosol samples; 15/35 Results Mtb (42.8%) samples were positive by mycobacterial culture and 25/27 (92.96%) were positive by ddPCR. Culturability of collected bacilli was not predicted by radiographic evidence of pulmonary cavitation, sputum smear positivity. A correlation was found between cough rate and culturable bioaerosol.was Mtb detected on all viable cascade impactor stages with a peak at aerosol sizes 2.0-3.5μm. This suggests a median of 0.09 CFU/litre of exhaled air (IQR: 0.07 to 0.3 CFU/l) for the aerosol culture positives and an estimated median concentration of 4.5x10 CFU/ml (IQR: 2.9x10 -5.6x10 ) of exhaled particulate bio-aerosol.: was identified in bio-aerosols exhaled by the majority of Conclusions Mtb untreated TB patients using the RASC. Molecular detection was more sensitive than mycobacterial culture on solid media, suggesting that further studies are required to determine whether this reflects a significant proportion of Page 1 of 25Gates Open Research 2018, 1:11 Last updated: 09 JUL 2018 Gates Open Research Discuss this article(1) Comments than mycobacterial culture on solid media, suggesting that further studies are required to determine whether this reflects a significant proportion of differentially detectable bacilli in these samples.

Using of Digital Droplet PCR in the detection of Mycobacterium tuberculosis DNA with FFPE and Cytological samples

“…As the advantage of ddPCR in the detection of target genes, the application of ddPCR in some tumor oncogenic gene test is now in the clinical registration stage [21] . Previously, studies also showed the application of digital PCR in TB detection using a different type of samples, such as MTB strains [22] , patient plasma [23] , human respiratory aerosol [24] , monkey blood [25] and human sputum [26] . Suporn Pholwat compared Real-time PCR, Sanger Sequencing and Digital PCR using stable extensively drug resistant (XDR) MTB strains.…”

Detection of Tuberculosis by The Analysis of Exhaled Breath Particles with High-resolution Mass Spectrometry

“…The work we present here pushes beyond the EBC collection to capture particulate matter emanating from the lungs 22 . This exhaled breath aerosol (EBA) sample collection technique was developed to capture bioaerosol particles which contain lung surfactant and microparticle fractions associated with the transmission of infectious diseases 11,12 . EBA-based collection methods offer several advantages.…”

“…Since EBA sampling methods focus on aerosol particles, study participants do not necessarily make direct contact with the sampling apparatus and saliva/sputum contamination can be avoided during the sample collection . The respired aerosol particles are also analyzed using optical scatter spectrometers to provide a quantitative aerosol particle size distribution that enables sampling standardization 11,12 . In our previous study, we developed an aerosol sampling system, respiratory aerosol sampling chamber (RASC), for the isolation and collection of breath aerosol particles 11 .…”

“…In our previous study, we developed an aerosol sampling system, respiratory aerosol sampling chamber (RASC), for the isolation and collection of breath aerosol particles 11 . Preliminary studies conducting on newly diagnosed tuberculosis (TB) patients demonstrated that advanced EBA collection method had the capacity to isolate airborne particles and organic substances including Mycobacterium tuberculosis, as confirmed by microbiological culture and polymerase chain reaction method 11,12 . The success of RASC-based aerosol particle collection encouraged us to develop a strategy by which biomolecules contained in aerosol particles can be characterized and used for the detection of active TB cases.…”

“…For this reason, it offers a potential for development of an advanced diagnostic tool with improved sensitivity, enhanced dynamic range, and unparalleled mass accuracy 10 . In previous studies, we developed a breath aerosol sampling unit, Respiratory Aerosol Sampling Chamber (RASC), to collect exhaled bioaerosol particles emitted from the lungs of active TB patients 11,12 . In this study, we developed a strategy to exploit the bioaerosol sampling system and high-resolution mass spectrometry for the characterization of biomolecules for the detection of positive TB cases.…”